SOST and sclerosteosis: The clinical importance of sclerostin was initially highlighted by sclerosteosis and van Buchem disease, two sclerosing bone disorders caused by loss-of-function mutations of the SOST gene (encoding sclerostin), and further proved by the phenotypical characterization of increased bone mass and bone formation in disease-related animal models (Li et al., 2008; Van Lierop et al., 2011, 2013; Boudin et al., 2017).